Common human scabies, caused by the mite, Sarcoptes scabiei, is an important, wide-spread, highly contagious skin disease of man. Continued high incidence and epidemics occur despite the presence of various therapies. There are various speculative views expressed to explain the continued high incidence of scabies but few are based on modern substantiated, thorough research of the basic biology of the mite and general host-parasite interaction. The long term objectives of this research are to investigate the basic biology and host-parasite interactions of this parasite in order to elucidate important factors that influence the infestation, transmission and epidemiology of both human and animal scabies. Results of this reserch will lead to a better understanding of factors that promote or retard the disease, better management of the disease, and subsequently reduced levels and/or eradication of the disease. The specific aims of the research are fourfold. First, it is a detailed analysis of the basic biology of the mite (e.g. life history, survival and infestivity, and host seeking and exploitatin behavior). This aim will be accomplished by direct observation of mites on the host, determinations of survival and retained infestability experiments of mites dislodged from the host, and observations of mite behavioral respones to various host stimuli. Secondly, the questions of host specificity and strain differences will be investigated. Physiological, morphological, behavioral and immunological differences will be identified by cross host transmission, electron microscopy, cross strain mating and cross antigenicity studies. Thirdly, efforts will be made to develop further an in vitro culture method for scabies mites. These experiments will involve refinement of climatic, physical and nutritional parameters of culture media and substrate conditions by trial and error and substitution experiments. Fourthly, the reserch will charcterize the antigenicity of S. scabiei var canis, the cross antigenicity between scabies mites and house dust mites and specific aspects of the host immune response in scabies infested rabbits and patients by crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis.